AB1011 CO-DIAGNOSIS SPONDYLOARTHRITIS AND INFLAMMATORY BOWEL DISEASE: THE ENTRY MODE MATTERS
Authors: J. Michel, C. Prati, L. Vuitton, D. Wendling, F. Verhoeven
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> There is a clear pathophysiological link between spondyloarthritis (SpA) and Inflammatory Bowel Disease (IBD), so that 10% of IBD is estimated to have SpA and 10% of SpA is estimated to have IBD. Recently, Luchetti et al [1] demonstrated an increased level of bacterial translocation in cases of co-diagnosis of SpA and IBD compared to patients with IBD alone. These data suggest that the presence of this codiagnosis is associated with a more inflammatory and therefore a more active pathology. <h3>Objectives</h3> The aim of this study is to describe this population and to evaluate the impact of timing of diagnoses. <h3>Methods</h3> A single-centre retrospective observational study was conducted. We included all consecutive patients followed between 2015 and 2022 for spondyloarthritis (SpA) meeting the ASAS 2009 criteria and IBD histologically proven. For each patient, we collected demographics, smoking, extrarticular manifestations, imaging data and the number of bDMARDs used and bDMARD combinations. We then compared the populations according to first diagnosis, SpA or IBD. Fischer's exact test was used for comparison between categorical variables and Student's t test for quantitative variables. <h3>Results</h3> A total of 62 patients, 51% male and 67% HLA B27+, were included. In 61% of the cases, IBD was diagnosed first. The majority of IBD patients were diagnosed with Crohn's disease (68%) with a mean age at diagnosis of 35.7 (±12.9) years. Concerning spondyloarthritis, it was mostly axial (95%), 55% of which was radiographic axial, with a mean age at diagnosis of 36.8 (±13.4) years. Psoriasis was present in 24% and uveitis in 24% of cases, active smoking in 66%, and a physical job in 20% of cases. Patients had used an average of 3 bDMARDs and 10% are treated with a combination of bDMARDs. When SpA was diagnosed first, patient characteristics were different from those whose IBD was diagnosed first, with a mean age at diagnosis of SpA of 29.8 (±11.6) years (versus 41.6 (±12.6) years; P&lt; 0.001) and a mean age at diagnosis of IBD of 31.9 (±11.8) years (versus 38.6 (+/-13) years; p= 0.043). When the codiagnosis was initiated by SpA, the prevalence of HLA B27 was 83% (versus 42%; p&lt;0.01), psoriasis 17% (versus 29%; p=0.27) and uveitis 35% (versus 16%; p=0.087). Finally, radiographic damage was more frequent when SpA started first, with 86% of radiographic sacroiliitis (versus 34%; p&lt; 0.001) and 44% of syndesmophytes (versus 13%; p= 0.036). <h3>Conclusion</h3> The population of patients with a co-diagnosis of SpA and IBD is a particular and difficult to treat population with an average of 3 different bDMARDs used and 10% of bDMARDs combination. Within this population, we identified two different clusters of patients according to the first diagnosis. <h3>Reference</h3> [1]Luchetti MM, Ciccia F, et al. Gut epithelial impairment, microbial translocation and immune system activation in inflammatory bowel disease-associated spondyloarthritis. Rheumatology (Oxford). 2021 Jan 5;60(1):92-102. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.